Type 2 diabetes impairs pulmonary function in morbidly obese women: a case-control study

Liraglutide Improves Forced Vital Capacity in Individuals With Type 2 Diabetes: Data From the Randomized Crossover LIRALUNG Study

To evaluate the effect of liraglutide, a glucagon-like peptide 1 receptor agonist, on pulmonary function and serum levels of surfactant protein D (SP-D) in type 2 diabetes. A double-blind, randomized, crossover, placebo-controlled clinical trial comprising 76 patients with a baseline forced expiratory volume in 1 s <90% of that predicted. Liraglutide was administered for 7 weeks (2 weeks of titration plus 5 weeks at 1.8 mg daily). This short duration was intentional to minimize weight loss as a potential confounding factor. Serum level of SP-D was used as a biomarker of alveolar-capillary barrier integrity. Liraglutide exerted a positive impact on forced vital capacity (FVC) in comparison with placebo (ΔFVC 5.2% of predicted [from 0.8 to 9.6]; P = 0.009). No differences in the other pulmonary variables were observed. Participants under liraglutide treatment also experienced a decrease in serum SP-D (P = 0.038). The absolute change in FVC correlated with final serum SP-D in participants receiving liraglutide (r = -0.313, P = 0.036). Stepwise multivariate regression analysis showed that final serum SP-D independently predicted changes in FVC. In conclusion, liraglutide increased FVC in patients with type 2 diabetes. This effect was associated with a significant decrease of circulating SP-D, thus pointing to a beneficial effect in the alveolar-capillary function.

Medications and medical costs for diabetes patients with or without chronic respiratory disease in Beijing, China: A retrospective study

AIMS

The cost of drug regimens prescribed to Chinese patients has not been evaluated. This study aims to evaluate the medical costs and hypoglycemic agents for diabetes mellitus patients with or without chronic respiratory disease in Beijing, and to investigate the changes in the costs and number of antidiabetic medications used for diabetes patients with chronic respiratory disease from 2016 to 2018.

METHODS

This observational, retrospective study included diabetes patients with outpatient medication records from Beijing Medical Insurance between 2016 and 2018. The medications, including hypoglycemic and nonhypoglycemic drugs, insulin dosage, comorbidities, diabetes-related complications, treatment strategies, and annual medical costs, were recorded.

RESULTS

This study included 2,853,036 diabetes patients from 2016 to 2018. About 18.95%-20.53% of patients with chronic respiratory disease were predominantly distributed among those aged 45-84 years (88.7%-89.1%). Diabetes patients with chronic respiratory disease used more medications (4.48 ± 2.41 vs. 3.76 ± 2.33) and had higher total annual drug costs (¥12,286 ± 10,385 vs. ¥9700 ± 9202) to treat more comorbidities (2.52 ± 1.53 vs. 2.05 ± 1.85) than those without chronic respiratory disease (p <.0001, respectively). From 2016 to 2018, diabetes patients with chronic respiratory disease had a 4.2% increase in medication, a 1.9% decrease in comorbidities, and a 5.4% decrease in total annual drug costs.

CONCLUSIONS

In summary, diabetes patients with chronic respiratory disease had more comorbidities, required more hypoglycemic drugs, and had higher medical costs. During 2016-2018, diabetes patients with chronic respiratory disease used more medications and spent less money on medical care.

Effect of Type 2 Diabetes Mellitus and Diabetic Medication on Pulmonary Function

Background:

Type 2 diabetes mellitus (T2DM) is a chronic condition with an impairing effect on multiple organs. Numerous respiratory disorders have been observed in patients with T2DM. However, the effect of T2DM on pulmonary function is inconclusive.

Aims:

In this study, we investigated the effect of T2DM on respiratory function and the correlation of glycemic control, diabetes duration and insulin intake.

Methods:

1500 patients were recruited for this study; 560 having T2DM for at least a year were included in the final data, in addition to 540 healthy volunteers. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory flow at 25-75% (FEF 25-75%), as well as FEV1/FVC ratio values were measured.

Results:

A two-sample t-test showed that z-scores produced by Al-Qerem et al.’s equations for FEV1, FVC, and FEF 25-75% were significantly lower for the T2DM group than the control group (p < 0.01). FEV1/FVC ratio in the T2DM group was significantly higher (p < 0.01). Multiple linear regression analysis found that glycemic control represented by HbA1c as well as disease duration were negatively associated with the pulmonary function (p < 0.01). However, insulin intake was found to have no significant correlation with pulmonary function.

Conclusion:

T2DM was linked to reduced pulmonary function and was consistent with a restrictive ventilation pattern. HbA1c, as well as disease duration, were found to be independent risk factors for reduced pulmonary function.

Genetic Correlation and Bidirectional Causal Association Between Type 2 Diabetes and Pulmonary Function

BACKGROUND

Observational studies have shown possible bidirectional association between type 2 diabetes (T2D) and pulmonary function, but the causality is not well defined. The purpose of this study is to investigate genetic correlation and causal relationship of T2D and glycemic traits with pulmonary function.

METHODS

By leveraging summary statistics from large-scale genome-wide association studies, linkage disequilibrium score regression was first implemented to quantify genetic correlations between T2D, glycemic traits, and several spirometry indices. Then both univariable and multivariable Mendelian randomization analyses along with multiple pleiotropy-robust methods were performed in two directions to assess the causal nature of these relationships.

RESULTS

Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) showed significant genetic correlations with T2D and fasting insulin levels and suggestive genetic correlations with fasting glucose and hemoglobin A1c. In Mendelian randomization analyses, genetically predicted higher FEV1 (OR = 0.77; 95% CI = 0.63, 0.94) and FVC (OR = 0.82; 95% CI = 0.68, 0.99) were significantly associated with lower risk of T2D. Conversely, genetic predisposition to higher risk of T2D exhibited strong association with reduced FEV1 (beta = -0.062; 95% CI = -0.100, -0.024) and FEV1 (beta = -0.088; 95% CI = -0.126, -0.050) and increased FEV1/FVC ratio (beta = 0.045; 95% CI = 0.012, 0.078). We also found a suggestive causal effect of fasting glucose on pulmonary function and of pulmonary function on fasting insulin and proinsulin.

CONCLUSIONS

The present study provided supportive evidence for genetic correlation and bidirectional causal association between T2D and pulmonary function. Further studies are warranted to clarify possible mechanisms related to lung dysfunction and T2D, thus offering a new strategy for the management of the two comorbid diseases.

Pulmonary function tests in type 2 diabetes: a meta-analysis

OBJECTIVES

The aim of this study was to determine the association between type 2 diabetes (T2D) and pulmonary function tests.

METHODS

After conducting an exhaustive literature search, we performed a meta-analysis. We employed the inverse variance method with a random-effects model to calculate the effect estimate as the mean difference (MD) and 95% confidence interval (CI). We calculated the heterogeneity with the I2 statistic and performed a meta-regression analysis by sex, body mass index (BMI), smoking and geographical region. We also conducted a sensitivity analysis according to the studies' publication date, size of the T2D group and the study quality, excluding the study with the greatest weight in the effect.

RESULTS

The meta-analysis included 66 studies (one longitudinal, two case-control and 63 cross-sectional), with 11 134 patients with T2D and 48 377 control participants. The pooled MD (95% CI) for the predicted percentage of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), forced expiratory flow at 25-75% of FVC, peak expiratory flow, and diffusing capacity of the lung for carbon monoxide were -7.15 (95% CI -8.27, -6.03; p<0.001), -9.21 (95% CI -11.15, -7.26; p<0.001), -9.89 (95% CI -14.42, -5.36; p<0.001), -9.79 (95% CI -13.42, -6.15; p<0.001) and -7.13 (95% CI -10.62, -3.64; p<0.001), respectively. There was no difference in the ratio of FEV1/FVC (95% CI -0.27; -1.63, 1.08; p=0.69). In all cases, there was considerable heterogeneity. The meta-regression analysis showed that between studies heterogeneity was not explained by patient sex, BMI, smoking or geographical region. The findings were consistent in the sensitivity analysis.

CONCLUSIONS

T2D is associated with impaired pulmonary function, independently of sex, smoking, BMI and geographical region. Longitudinal studies are needed to investigate outcomes for patients with T2D and impaired pulmonary function.

Comprehensive Pulmonary Safety Review of Inhaled Technosphere® Insulin in Patients with Diabetes Mellitus

BACKGROUND AND OBJECTIVE

Technosphere® Insulin (TI), a human insulin powder for inhalation (Afrezza®; MannKind Corporation, Westlake Village, CA, USA), is an ultra-rapid-acting inhaled insulin indicated to improve postprandial glycemic control in patients with type 1 or type 2 diabetes mellitus (T1DM or T2DM). Because TI is absorbed across the alveolar membrane, the objective of this analysis was to characterize its pulmonary safety.

METHODS

Pooled data from 13 phase 2/3 clinical studies in 5505 patients with T1DM or T2DM treated with TI, Technosphere inhalation powder without insulin (TP; placebo), or active-comparator treatment were analyzed for incidences of respiratory treatment-emergent adverse events (TEAEs), changes in pulmonary function, and lung malignancies. Radiographic changes in the lungs were monitored in a subset of 229 patients.

RESULTS

Among 3017 patients receiving TI, the median duration of TI exposure was 168 days; median active-comparator and TP exposure durations were 363 and 149 days for 2198 and 290 patients, respectively. Respiratory TEAEs were comparable across treatments, except for a higher incidence of mild cough with TI in active-comparator studies (28.0% vs. 5.2%). Slight reversible declines in pulmonary function from baseline were observed for TI versus TP and active-comparator treatments, including in a subpopulation of patients with retrospectively identified lung dysfunction. Lung malignancies were reported in two patients on active TI therapy with a smoking history. No clinically significant changes from baseline were observed in radiographic images.

CONCLUSIONS

Pulmonary safety assessment of the TI inhalation system did not identify any safety issues in individuals with either T1DM or T2DM.

Pre- and postoperative respiratory muscle strength, body mass index and fasting glucose profile of patients with type 2 diabetes mellitus submitted to metabolic surgery

Abstract Introduction: The lung is considered a target organ in diabetes mellitus as a consequence of alterations secondary to chronic hyperglycemia that compromise respiratory muscle strength. Metabolic surgery for improving diabetes mellitus has beneficial effects on weight loss and glucose metabolism. Objective: The objective of this study was to evaluate the respiratory muscle strength, assessed by MIP and MEP, body mass index (BMI) and fasting glucose profile of patients with type 2 diabetes mellitus before and after metabolic surgery without gastric resection. Method: Seventeen patients with type 2 diabetes mellitus participated in the study. The participants had a mean age of 44.8 ± 11.81 years. Results: The results showed a significant decrease of MEP values in the immediate postoperative period when compared to the preoperative period (p=0.001), while no significant results were obtained for MIP. Regarding BMI and fasting glucose, significant weight loss and a significant reduction in fasting glucose levels were observed in the late postoperative period (p=0.006 and p=0.007, respectively). Conclusion: The MIP and MEP were reestablished and satisfactory results were obtained for BMI and fasting glucose in the late postoperative period. Further studies are needed to monitor patients in the pre- and postoperative period of metabolic surgery, identifying complications and acting on the care and recovery of these patients.

Pulmonary Pathology Among Patients with Type 2 Diabetes Mellitus: An Updated Systematic Review and Meta-analysis

BACKGROUND

Restrictive lung pathology was reported in the previous meta-analysis among patients with Type 2 Diabetes mellitus (T2DM) which is date back to 2010.

OBJECTIVE

To see the effect of T2DM on pulmonary functions through updated systematic review and meta-analysis.

DATA SOURCE

PubMed.

STUDY ELIGIBILITY CRITERIA

English language case-control or cross-sectional studies, published between 1 January 2010 to 31 August 2018.

PARTICIPANTS AND INTERVENTION

T2DM and non-diabetic subjects were compared for at least one of the pulmonary function variables i.e. Forced expiratory volume in 1st second (FEV1), % FEV1, Forced vital capacity (FVC), % FVC and % FEV1/FVC.

STUDY APPRAISAL AND SYNTHESIS METHODS

Methodological quality of the study was assessed using Newcastle-Ottawa Quality Assessment Scale. Meta-analysis was done using Review Manager 5.3 (RevMan 5.3) and meta-regression was conducted using R statistical software.

RESULTS

We selected 22 articles that met our inclusion and exclusion criteria. Results reveal that among patients with T2DM all variables were reduced except %FEV1/FVC which shows statistically nonsignificant results with P=0.46. This confirms that T2DM patients have a restrictive type of lung pathology.

LIMITATION

Only articles from the PubMed database were included. Conclusion and Implications of Key Findings: This review affirms the existing evidence of restrictive pathology among patients with T2DM. The future study could be conducted to see the effect of various rehabilitation protocols on pulmonary function among patients with T2DM.

Long-term observational study on the impact of GLP-1R agonists on lung function in diabetic patients

INTRODUCTION

Preclinical research suggests a role of Glucagon Like Peptide-1 Receptors (GLP-1R) on the regulation of human bronchial tone. We investigated the effect of GLP-1R agonists on lung function of Type 2 Diabetes Mellitus (T2DM) population without co-existing chronic obstructive respiratory disorders.

METHODS

This was a prospective cohort study that examined change in lung function measurements over two years of T2DM patients (n = 32) treated with metformin monotherapy (control cohort), metformin plus GLP-1R agonists (GLP-1R agonists cohort), or metformin plus insulin (insulin cohort).

RESULTS

After 24 months of treatment, the forced expiratory volume in 1 s (FEV₁) significantly (p < 0.05) increased from baseline in the GLP-1R agonists cohort (218 ml [95%CI 88-246]), but not in the control and insulin cohorts (94 ml [95%CI -28 - 216] and 26 ml [95%CI -174 - 226], respectively; p > 0.05 vs. baseline). The average increase in FEV₁ in the GLP-1R agonists cohort was significantly greater than that in the control and insulin cohorts (delta: 110 ml [95%CI 18-202] and 177 ml [95%CI 85-270], respectively, p < 0.05). The forced vital capacity (FVC) also increased significantly more in the GLP-1R agonists cohort than in the control and insulin cohorts (overall delta FVC: 183 ml [95%CI 72-295], p < 0.05). The maximal expiratory flow at 50-75% significantly (p < 0.05) improved from baseline in the GLP-1R agonists cohort, but not in the control and insulin cohorts (p > 0.05).

CONCLUSION

Our preliminary results suggest a potential new therapeutic perspective to treat airway disorders with GLP-1R agonists.

Effect of Glucose Improvement on Spirometric Maneuvers in Patients With Type 2 Diabetes: The Sweet Breath Study

OBJECTIVE

Type 2 diabetes exerts a deleterious effect on lung function. However, it is unknown whether an improvement in glycemic control ameliorates pulmonary function.

RESEARCH DESIGN AND METHODS

Prospective interventional study with 60 patients with type 2 diabetes and forced expiratory volume in 1 s (FEV1) ≤90% of predicted. Spirometric maneuvers were evaluated at baseline and after a 3-month period in which antidiabetic therapy was intensified. Those with an HbA_1c reduction of ≥0.5% were considered to be good responders (n = 35).

RESULTS

Good responders exhibited a significant improvement in spirometric values between baseline and the end of the study (forced vital capacity [FVC]: 78.5 ± 12.6% vs. 83.3 ± 14.7%, P = 0.029]; FEV1: 75.6 ± 15.3% vs. 80.9 ± 15.4%, P = 0.010; and peak expiratory flow [PEF]: 80.4 ± 21.6% vs. 89.2 ± 21.0%, P = 0.007). However, no changes were observed in the group of nonresponders when the same parameters were evaluated (P = 0.586, P = 0.987, and P = 0.413, respectively). Similarly, the initial percentage of patients with a nonobstructive ventilatory defect and with an abnormal FEV1 decreased significantly only among good responders. In addition, the absolute change in HbA_1c inversely correlated to increases in FEV1 (r = -0.370, P = 0.029) and PEF (r = -0.471, P = 0.004) in the responders group. Finally, stepwise multivariate regression analysis showed that the absolute change in HbA_1c independently predicted increased FEV1 (R ² = 0.175) and PEF (R ² = 0.323). In contrast, the known duration of type 2 diabetes, but not the amelioration of HbA_1c, was related to changes in forced expiratory flow between 25% and 75% of the FVC.

CONCLUSIONS

In type 2 diabetes, spirometric measurements reflecting central airway obstruction and explosive muscle strength exhibit significant amelioration after a short improvement in glycemic control.

Pulmonary Function and Sleep Breathing: Two New Targets for Type 2 Diabetes Care

Population-based studies showing the negative impact of type 2 diabetes (T2D) on lung function are overviewed. Among the well-recognized pathophysiological mechanisms, the metabolic pathways related to insulin resistance (IR), low-grade chronic inflammation, leptin resistance, microvascular damage, and autonomic neuropathy are emphasized. Histopathological changes are exposed, and findings reported from experimental models are clearly differentiated from those described in humans. The accelerated decline in pulmonary function that appears in patients with cystic fibrosis (CF) with related abnormalities of glucose tolerance and diabetes is considered as an example to further investigate the relationship between T2D and the lung. Furthermore, a possible causal link between antihyperglycemic therapies and pulmonary function is examined. T2D similarly affects breathing during sleep, becoming an independent risk factor for higher rates of sleep apnea, leading to nocturnal hypoxemia and daytime sleepiness. Therefore, the impact of T2D on sleep breathing and its influence on sleep architecture is analyzed. Finally, the effect of improving some pathophysiological mechanisms, primarily IR and inflammation, as well as the optimization of blood glucose control on sleep breathing is evaluated. In summary, the lung should be considered by those providing care for people with diabetes and raise the central issue of whether the normalization of glucose levels can improve pulmonary function and ameliorate sleep-disordered breathing. Therefore, patients with T2D should be considered a vulnerable group for pulmonary dysfunction. However, further research aimed at elucidating how to screen for the lung impairment in the population with diabetes in a cost-effective manner is needed.

Serum Surfactant Protein D as a Biomarker for Measuring Lung Involvement in Obese Patients With Type 2 Diabetes

CONTEXT

Lung impairment is a new target for late diabetic complications. Biomarkers that could help identify patients requiring functional respiratory tests have not been reported.

OBJECTIVE

Our aim was to examine whether serum surfactant protein D (SP-D) and A (SP-A) could be useful biomarkers of lung damage in obese patients with type 2 diabetes (T2D) without known lung disease.

DESIGN AND SETTING

A case-control study conducted in an ambulatory obesity unit.

PATIENTS

Forty-nine obese patients with T2D and 98 subjects without diabetes matched by age, sex, body mass index, and waist circumference were included.

INTERVENTIONS

Serum SP-D and SP-A levels were measured using enzyme-linked immunosorbent assay. Forced spirometry and static pulmonary volume were assessed.

RESULTS

Patients with T2D exhibited higher serum SP-D concentrations than control subjects (P = 0.006). No differences in serum SP-A concentrations were observed. There was an inverse association between forced expiratory volume in 1 second (FEV1) and serum SP-D (r = -0.265; P = 0.029), as well as a significant positive relationship between SP-D concentration and residual volume (r = 0.293; P = 0.043). From receiver operating characteristic analysis, the best SP-D cutoff to identify a FEV1 <80% of predicted was 132.3 ng/mL (area under the curve, 0.725; sensitivity, 77.7%; specificity, 69.4%). Stepwise multivariate regression analysis showed that serum SP-D concentration ≥132.3 ng/mL was independently associated with a FEV1 <80% of predicted (R2 = 0.406). Only the existence of T2D contributed independently to serum SD-P variance among all subjects (R2 = 0.138).

CONCLUSIONS

Serum SP-D concentration can be a useful biomarker for detecting lung impairment in obese patients with T2D.

No mediating effects of glycemic control and inflammation on the association between vitamin D and lung function in the general population

BACKGROUND

Vitamin D deficiency is discussed to be associated with lung health. While former studies focused on subjects suffering from pulmonary diseases, we aimed to investigate the association of 25-hydroxy vitamin D [25(OH)D] with lung function in the general population and examined whether mediating effects of inflammation, glycemic control or renal function exist.

METHODS

1404 participants from the Study of Health in Pomerania with pulmonary function testing assessed by expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), total lung capacity and Krogh index were used. Adjusted analysis of variance, linear regression models and mediation analyses were performed.

RESULTS

Significant positive associations between 25(OH)D levels and FEV₁, FVC and Krogh index were found. Mediator analyses revealed no mediating effect of inflammation (fibrinogen), glycemic control (HbA1c) or renal function (eGFR) on associations with FEV₁ or FVC. With respect to Krogh-Index, the association to 25(OH)D was slightly mediated by fibrinogen with a proportion mediated of 9.7%.

CONCLUSION

Significant positive associations of 25(OH)D with lung function were revealed in a general population. The proposed mediating effects of inflammation, glycemic control and renal function on these relations were not confirmed. Further studies examining the causality of the association between 25(OH)D and lung function are necessary.

Association between lung capacity and abnormal glucose metabolism: findings from China and Australia

OBJECTIVE

Restricted pulmonary function is found among people with diabetes. This study aimed to investigate the dose-response relationship between pulmonary function measurements [forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)] and risk of metabolic syndrome (MS)/type 2 diabetes.

METHODS

A total of 1454 adults in rural Victoria, Australia, and 5824 adults in Nanjing, China, from randomly selected households provided clinical history, oral glucose tolerance test, lipids, anthropometric, blood pressure and spirometric measurements. MS was defined by International Diabetes Federation criteria. Adjusted odds ratios for MS and type 2 diabetes with lung capacity measurements were estimated using logistic regression. Dose-response relationships were explored using the restricted cubic spline models.

RESULTS

There was a nonlinear relationship between FEV1 and the risk of type 2 diabetes and MS (both P < 0·0001) in both the Australian and Chinese populations. The FEV1 associated with the lowest risk of type 2 diabetes and MS was above 2·70 l (95%CI: 2·68 to 2·72 l and 2·65 to 2·76 l in Chinese and Australian populations, respectively). The discrimination of the model could be significantly improved using the FEV1 threshold in both the Australian and Chinese populations.

CONCLUSIONS

In both the Australian and Chinese populations, the risk of type 2 diabetes and MS is lowest with a FEV1 of 2·65-2·76 l. This might be used in clinical practice in different countries as a prompt to screen for type 2 diabetes and MS in patients with obstructive lung disease and to ensure there was no abnormal glucose metabolism before the commencement of steroids if indicated.

Characterization of sleep breathing pattern in patients with type 2 diabetes: sweet sleep study

BACKGROUND

Although sleep apnea-hypopnea syndrome (SAHS) is highly prevalent in patients with type 2 diabetes (T2D), it is unknown whether or not subjects with and without T2D share the same sleep breathing pattern.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional study in patients with SAHS according to the presence (n = 132) or not (n = 264) of T2D. Both groups were matched by age, gender, BMI, and waist and neck circumferences. A subgroup of 125 subjects was also matched by AHI. The exclusion criteria included chronic respiratory disease, alcohol abuse, use of sedatives, and heart failure. A higher apnea hypopnea index (AHI) was observed in T2D patients [32.2 (10.2-114.0) vs. 25.6 (10.2-123.4) events/hours; p = 0.002). When sleep events were evaluated separately, patients with T2D showed a significant increase in apnea events [8.4 (0.1-87.7) vs. 6.3 (0.0-105.6) e/h; p = 0.044), as well as a two-fold increase in the percentage of time spent with oxygen saturation <90% [15.7 (0.0-97.0) vs. 7.9 (0.0-95.6) %; <0.001)], higher rates of oxygen desaturation events, and also higher daily sleepiness [7.0 (0.0-21.0) vs. 5.0 (0.0-21.0); p = 0.006)] than subjects without T2D. Significant positive correlations between fasting plasma glucose and AHI, the apnea events, and CT90 were observed. Finally, multiple linear regression analyses showed that T2D was independently associated with AHI (R2 = 0.217), the apnea index (R2 = 0.194), CT90 (R2 = 0.222), and desaturation events.

CONCLUSIONS/SIGNIFICANCE

T2D patients present a different pattern of sleep breathing than subject without diabetes. The most important differences are the severity of hypoxemia and the number of apneas whereas the incidence of hypopnea episodes is similar.

Effect of glycemic control on nocturnal arterial oxygen saturation: a case-control study in type 2 diabetic patients

BACKGROUND

There is growing evidence suggesting a deleterious effect of type 2 diabetes on lung function and sleep breathing. The aim of this case-control study was to evaluate whether or not an improvement in glycemic control could arrest or ameliorate nocturnal hypoxemia in type 2 diabetes.

METHODS

Thirty patients with type 2 diabetes with HbA1c ≥8% (cases) and 10 non-diabetic subjects were analyzed. Controls were closely matched to cases by age, gender, body mass index, and neck circumference. The nocturnal oxygen desaturation index (ODI) was calculated at baseline and 5 days after blood glucose improvement with pharmacological intervention. Four different oxygen desaturation thresholds (reductions in SaO2  ≥ 3%, 4%, 6%, and 8%) as indicators of hypoxemia severity (ODI-3%, ODI-4%, ODI-6%, ODI-8%) were used.

RESULTS

At baseline, patients with diabetes showed a higher number of ODI-3%, ODI-4%, and ODI-6% in comparison with controls. A significant reduction in ODI-3% (29.7 [4.8-107.9] events per hour at baseline versus 24.6 [3.1-97.7] e/h at discharge, P < 0.001), ODI-4% (21.7 [1.6-79.3] versus 14.7 [0.3- 79.4], P = 0.003), ODI-6% (9.3 [0.3-71.8] versus 4.0 [0.0-73.7], P = 0.001), and ODI-8% (4.1 [0.0-64.3] versus 1.1 [0.0-69.8], P = 0.033) was observed in patients with diabetes after 5 days of follow-up. However, no changes in ODI events were observed in non-diabetic patients after the same period. No significant changes in weight were observed in either group.

CONCLUSIONS

Glycemic control improvement significantly reduces the increased number of nocturnal oxygen desaturations that exist in type 2 diabetes. Although the mechanisms are not yet fully understood, the rapid effect without changes in body weight suggests a central mechanism involving respiratory center output.

Association between lung capacity measurements and abnormal glucose metabolism: findings from the Crossroads study

AIM

To examine the association between lung function and metabolic syndrome/Type 2 diabetes.

METHODS

A total of 1454 adults from rural Victoria, Australia, from randomly selected households included in the Crossroads study, provided spirometric measurements including forced vital capacity, forced expiratory volume in 1 s, predicted percentage value of forced expiratory volume in 1 s and forced vital capacity predicted percentage value. Assessments also included HbA(1c), metabolic syndrome components and a 75-g oral glucose tolerance test. The area under the receiver-operating characteristic curves for waist circumference were compared with those for combinations of waist circumference and raw spirometric measures (forced vital capacity and forced expiratory volume in 1 s) for identifying metabolic syndrome or Type 2 diabetes.

RESULTS

Partipants with a greater number of metabolic syndrome components were more likely to have reduced lung function, particularly if Type 2 diabetes was present: the predicted value of forced expiratory volume in 1 s decreased by 5-6% for participants with 2-4 metabolic syndrome components, and by 9% for those with Type 2 diabetes. The risk of metabolic syndrome or Type 2 diabetes was inversely associated with higher spirometry values (forced expiratory volume in 1 s percentage predicted value: odds ratio for 2-4 metabolic syndrome components 0.36-0.21 in women and 0.32-0.30 men; the odds ratio for Type 2 diabetes was 0.36 in women and 0.28 in men). Receiver-operating characteristic curve analysis for identifying metabolic syndrome and Type 2 diabetes revealed significant differences between the area under the receiver-operating characteristic curve with waist circumference alone and that for the combination of waist circumference with lung capacity measures.

CONCLUSION

Pulmonary function is lower in people with metabolic syndrome and Type 2 diabetes. Spirometry variables are independent predictors of metabolic syndrome and Type 2 diabetes.

Claudin heterogeneity and control of lung tight junctions

Lung epithelial cells interconnected by tight junctions provide a barrier to the free diffusion of solutes into airspaces. Transmembrane tight junction proteins known as claudins are essential for epithelial barrier function. Claudins are regulated through interactions with each other that are coordinated with other transmembrane tight junction proteins and cytosolic scaffold proteins. Of the 14 claudins expressed by the alveolar epithelium, claudin-3, claudin-4, and claudin-18 are the most prominent; each confers unique properties to alveolar barrier function. In particular, a protective role for claudin-4 in preventing lung injury has emerged. By contrast, lung diseases that affect claudin expression and impair barrier function, including alcoholic lung syndrome and sepsis, prime the lung for pulmonary edema. Thus, approaches to restore and/or augment lung claudin expression provide potential targets for promoting healthy barrier function.

The modified Medical Research Council scale for the assessment of dyspnea in daily living in obesity: a pilot study

Background

Dyspnea is very frequent in obese subjects. However, its assessment is complex in clinical practice. The modified Medical Research Council scale (mMRC scale) is largely used in the assessment of dyspnea in chronic respiratory diseases, but has not been validated in obesity. The objectives of this study were to evaluate the use of the mMRC scale in the assessment of dyspnea in obese subjects and to analyze its relationships with the 6-minute walk test (6MWT), lung function and biological parameters.

Methods

Forty-five obese subjects (17 M/28 F, BMI: 43 ± 9 kg/m²) were included in this pilot study. Dyspnea in daily living was evaluated by the mMRC scale and exertional dyspnea was evaluated by the Borg scale after 6MWT. Pulmonary function tests included spirometry, plethysmography, diffusing capacity of carbon monoxide and arterial blood gases. Fasting blood glucose, total cholesterol, triglyceride, N-terminal pro brain natriuretic peptide, C-reactive protein and hemoglobin levels were analyzed.

Results

Eighty-four percent of patients had a mMRC ≥ 1 and 40% a mMRC ≥ 2. Compared to subjects with no dyspnea (mMRC = 0), a mMRC ≥ 1 was associated with a higher BMI (44 ± 9 vs 36 ± 5 kg/m², p = 0.01), and a lower expiratory reserve volume (ERV) (50 ± 31 vs 91 ± 32%, p = 0.004), forced expiratory volume in one second (FEV₁) (86 ± 17 vs 101 ± 16%, p = 0.04) and distance covered in 6MWT (401 ± 107 vs 524 ± 72 m, p = 0.007). A mMRC ≥ 2 was associated with a higher Borg score after the 6MWT (4.7 ± 2.5 vs 6.5 ± 1.5, p < 0.05).

Conclusion

This study confirms that dyspnea is very frequent in obese subjects. The differences between the “dyspneic” and the “non dyspneic” groups assessed by the mMRC scale for BMI, ERV, FEV₁ and distance covered in 6MWT suggests that the mMRC scale might be an useful and easy-to-use tool to assess dyspnea in daily living in obese subjects.

Update on cystic fibrosis-related diabetes

PURPOSE OF REVIEW

The aim is to provide a detailed review of recent publications on cystic fibrosis-related diabetes (CFRD) with a particular focus on the interplay between cystic fibrosis (CF) lung disease and diabetes.

RECENT FINDINGS

CFRD is a form of diabetes that is distinct from type 1 or type 2 diabetes. CFRD remains very common and increases in prevalence with increasing age so that one in two middle-aged CF persons have CFRD. People with CFRD have lower lung function, worse nutrition, more frequent hospitalization, and worse mortality than CF people without diabetes. The excess mortality previously noted in women with CFRD compared with CF women without diabetes or CF men is much less apparent. CFRD is due to insulin deficiency and peripheral insulin resistance is much less a factor. Genetic susceptibility and oxidant stress are key risk factors for developing CFRD. The lung is the prime end organ target in CFRD and mortality is due to respiratory failure, not vascular complications. Insulin is the mainstay of therapy and early recognition and institution of therapy appear to improve health outcomes.

SUMMARY

CFRD remains one of the most important co-morbidities in CF. Early recognition of the disease and therapeutic intervention may diminish the negative impact that diabetes has on lung health in CF. Although a clearer understanding of the role of oxidant stress and genetics in the pathogenesis of CFRD is being elucidated, much needs to be learned before more targeted, specific therapies can be developed for this distinct form of diabetes.